Machine for nibbling or punching metal and other sheets



Get. 8, 1946. G, H WEBB 223K393 MACHINE FOR NIBBLING OR PUNCHINGMETALfiND OTHER SHEETS Filed Jan. 10, '1939 I 2 Sheets-Sheet 1 v, tInventor w w w 2% 1 m /xmrw;

b ZZ A Home ma. 8, 1940. G. H. WEBB 2,217,393

MACHINE FDR NIBBLING OR PUNCHING METAL AND OTHER SHEETS Filed Jan. 10,1939 2 Sheets-Sheet 2 Patented Oct. 9

FATE.

FFICE mcnma ron. NIBBLING on PUNG METAL AND o'rnna snna'rs George HenryWebb, Edgware, England Application January 16, 1939, Serial No. 250,243'11! Great Britain All? 27, 1938 This invention relates to nibblingmachines having a reciprocating, punch of suitable section co-operatingwith a'iiie of appropriate shape carried by a relatively fixed frameworkor support,

of the known type in which the relatively fixed framework or supportcarrying the die comes to the rear of the reciprocating punch andadjacent thereto, so that relatively to the workpiece it can follow thesaid punch through a cut, caused by successive nibblings with anadequate feed.

The invention refers more particularly, although not exclusively, tosuch devices of a portable nature adapted to be moved (by hand orotherwise) in relation to the workpiece being operated upon. Thus, forexample,'such devices can be utilised for cutting sheet metal by beingmoved in relation thereto through a desired path.

In general, according to the'principal feature of the invention, thepunch has a section which includes a re-entrant portion at or towardsits rear, into which re-entrant portion the frame member or supportcarrying the die projects, so that the said re-entrant portion worksover and preferably in contact with such frame member or 25 support.

According to a further feature of the invention, the. die, which has acutting shape to cooperate with the forward and lateral surfaces of thepunch, has the part of the die coming to the rear of the said punchdiscontinuous or open to permit the location therein of the frame orsupport coming to the rear of the punch.

Although the invention is not limited thereto, the section of punch itis preferred to employ is 35 of general crescent or horseshoe shape, there-entrant boundary at the rear being somewhat semicircular or moreprecisely consists of a circumferential arc of somewhat less than 180terminating in slightly diverging tangents, whilst the 40 forward andlateral portions are comprised by somewhat more than a semicircle ofslightly greater diameter. To co-operate with this front and lateralcurvature of the punch the die has a cutting edge of similar shape theends of which extend rearwardly to form a slot for the accommodation ofthe frame member, this latter having a front generally semi-cylindricalpart to fit and engage in the re-entrant portion at the rear of thepunch.

It is preferred so to construct nibbling machines in accordance with theinvention that upon the stopping of the machine the punch is disengagedfrom the die, which normally would be the upper position, and for thispurpose and 55 in accordance with a further feature of the 17.1-

vention spring means are provided, which always assure the outwardstroke of the punch should the drive stop in any other position. In thismanner the tool when stopped is always readily withdrawn from orre-engaged with the workpiece 5 and further, the actual punch receivesits maximum impact force when re-starting before contacting with theworkpiece to be operated upon.

Devices according to the invention may be driven by any suitable means,for example by a 10 flexible or other shaft, or even by a self-containeddriving means. For example, such selfcontained driving means may, inaccordance with a further feature of the invention, be comprised by apneumatic, electric or other motor 15 wholly contained within the handleby which the device is held and manipulated in relation to the sheet ofmetal, or other workpiece being operated upon.

The invention comprises further features 20 which will be apparent fromthe following description.

In order that the invention may be better understood, it will now bedescribed with reference to the accompanying drawings, which are given25 by way of example and in which:

Fig. 1 shows in side elevation one form of nibbling machine constructedaccording to the invention, adapted to be operated by a pneumatic motorincluded in its handle.

Fig. 2 is an end view thereof, taken from the direction remote from theinlet for air.

Fig. 3 is a sectional side elevation to a large scale of a portion ofFig. 1.

Fig. 4 is an end elevation, partly in section, of a portion of Fig. 3.

Figs. 5, 6, 7 and 8 are sections on the lines 55, 8-8, 1-1 and ll8, Fig.3.

Fig. 9 is a somewhat diagrammatic plan hereafter referred to.

Fig. 10 is a perspective view, partly in section, of the frame member.

Fig. 11 shows a diagrammatic view, in three positions, to illustrate thereciprocating drive for the punch.

Fig. 12 shows a view somewhat similar to Fig. 8 but in which thereciprocating tool does not actually wholly contact with the framemember but is somewhat spaced from the portion of the frame member whichprojects into the re-entrant portion of the tool.

can be driven from a power line, from a flexible shaft, or any suitablepower-operated means, Further, they may include in their structurefluid-operated or electric motors. These fluidoperated or electricmotors in preferred cases are enclosed in the handle means by which thetool is manipulated.

The tool shown in Fig. 1 is driven by a pneumatic motor (not shown indetail as it can be of any known form) enclosed and totally containedwithin the somewhat cylindrical handle [0, H being the pipe line thereofand I2 the exterior means by which the inlet valve is opened and closed.As will be appreciated, this means I2 is adapted to be pressed down bythe hand gripping the handle i6 so that when so gripped the motor isstarted, whilst when the grip is released the motor stops.

The motor shaft either itself or another shaft driven through suitablegearing effects the drive and is denoted by a shaft l3 preferablymounted in ball bearings in the casing l and having an eccentricallyarranged crank-pin l4g, also mounted in ball bearings in a reciprocatingslide or plunger I5 working in a casing portion l6 arranged at rightangles to the casing iii. The crank I4 is mounted in the inner race of aball bearing the outer race of which is located in a recess 55 in theupper end of the plunger l5. As will be appreciated, when the shaft l3rotates the crank-pin l4 causes the reciprocation of the plunger IS, theouter race of this ball bearing moving slightly from side to side in therecess 55,

as will be seen from Fig. 11.

As will be realised, the casing l6 may be at any other angle than aright angle with respect to the casing l0 and even in some cases theangular relationship between the axes of the casing l0 and the casing l6may be adjustable. In this latter case any necessary mechanical jointsor other means are provided between the parts to accommodate the variedangular setting.

At its lower end the casing l6 has secured thereto by a union nut II aflanged frame member l8 shown in Fig. 10, to be hereafter more fullydescribed. The front of this frame member l3 has a channel l9 extendingfrom top to bottom, the upper portion of which is adapted to accommodatea lug or projection 26 at the front lower end of the casing l6 to enablethe frame member to be precisely set in position and to prevent angularmovement thereof.

Between the upper end of the frame member l3 and the 1ower end of thecasing i6 is secured by its flange 2| (also notched at 22 for the lug orprojection 20) a bush 23 which extends downwards into the upper hollowportion of the framework and is recessed to receive one end of acompressionspring 24, the other end'abutting the lower part of the slideor plunger I! through a collar 25.

The lower end of the said -slide or plunger l5 has a bore in which issecured the upper end of a punch 26 by means of a grub screw 21accessible through an opening 23 in the casing l6, the parts being soshaped and dimensioned that the punch has precise axial and angularsetting.

The punch, which is generally cylindrical throughout its length, has atits lower end to the rear and extending a desired distance upwardly. apart removed to leave the section thereof somewhat crescent shaped asshown generally'in Figs. 6, '7, 8 and 9. Particularly referring to Fig.9, this section has a re-entrant curvature 36 at the rear part ofsomewhat semicircular form, or more precisely consists of acircumferential arc of somewhat less than 180 terminating in slightlydiverging tangents, and its front and lateral portions have thecurvature of the exterior surface of the punch 26 which is a circle ofgreater diameter 5 than that of the re-entrant portion and consequentlyit is of slightly greater than semicircular extent and for the purposesof description may be regarded as having a front portion 3| and lateralportions 32.

The frame member l3, as will be seen clearly from Fig. 10, has the upperhollow cap-like part terminating in the flange (to be engaged by theunion nut I1) and with the upper portion of the channel l9. It' furtherincludes at its lower part a circular plate-like portion 33 (with thelower portion of the channel l9) to receive on its upper surface a die34, and the portion 33 is connected to the upper main cap-like part ofthe frame by a portion 35 the section of which is shown in Fig. 8 andcomprises a front somewhat semi-cylindrical part 36 (which also extendsupwards into the lower part of the cap portion and downwards into theplate 33, as shown in Figs. 3, 4 and 10) which is of such a size and sodisposed in the assembly that it enters into the re-entrant portion 30of the punch and forms a support and guide therefor. The portion extendsrearwardly, its sides 31 converging regularly or otherwise from thesemi-cylindrical front 36.

The die 34 is formed from a circular plate having its cutting edge 38 toco-operate with the front and sides 3| and 32 of the punch and theterminations of this cutting edge are slightly widened and extendedrearwardly by surfaces 33 35 to form a slot as shown in Fig. 8. Thisslot permits the die to be positioned with the portion 35 of the framein the slot.

4| is a cap member having a slot 42 extending diametrically across itsbase, the front of which slot coincides with the lower part of thechannel H3. The side walls of this cap fit around the plate portion 33and the die 34, which is of the same diameter as the plate, to act aspart locating means for the said die. The parts are fully located andsecured in position by screws 43 which engage in the base of the cap,pass through bores in the plate portion 33 and enter suitably tappedapertures 44 in the die.

The lower part of the cap portion of the frame l3 comes a desireddistance above the upper surface of the die to leave an entry apertureor mouth 45 for the tool to be passed on to the metal sheet such as 46or other workpiece and it should be observed from Fig. 3 that the diehas an upper surface with a flat portion 4'! adjacent its cutting edgeathe rest of the surface being slightly coned a The operation will bereadily understood. In the first place it should be observed that thecompression spring 24 assures that when the machine has stopped theplunger l5 and punch 26 have been brought to the upper position. Thisenables the mouth 45 fully to be passed on to the edge of the metalsheet so that the said edge contacts with the front semi-cylindricalportion 36 of the frame portion 35, with the lower end of the punchabove the metal sheet. This position is shown clearly in Fig. 3. Whenthe machine is when the punch again attains its upper position,

the semi-cylindrical portion 38 of the frame part 35 is pushed forwardsto make contact with that part of the sheet metal which has been cut bythe front part 3! of the punch and then the action 5 is repeated. In theresult and as shown in Fig. 9, a cut :19 is made in the sheet If by theseries of rapidly following punching operations, the edges of the outhaving slight undulations due to the lateral portions 32 of the punch.

The cut can follow any desired line as the converging portions 31 of'theframe member 35 permit curves of comparatively small radius to be cut.Again, the workpiece such as the sheet metal 66 need not have a planeconformation as the mouth 45 and die 34 with bevelled surface 48 enablesheets or the like of curved conformation also to be dealt with.

It should also be appreciated that as the hand grasping the casing 50(which in practical tools is about four inches long, the other partsbeing in proportion) comes closely adjacent the work and as moreoverthere are substantially no unbalanced masses, even a comparativelyunskilled operater can utilise the tool with great precision and followintricate paths of out including turns with facility.

Finally, in connection with the operation it should be understood thatthe relative shaping and juxtaposition of the punch and the frameportion give practicability and long life to the tool. The main reasonfor this is that the breaking or bending leverage on the frame portion35, due to the downward thrust of the punch on the metal which istransferred to the die, meets with 35 a maximum possible resistance dueto the fact that a strong section of the frame portion 35, i. e., g thesomewhat semicircular section 38, enters into the re-entrant portion ofthe punch and thus reduces the effective leverage to a minimum. Inaddition to the numerous advantages of a tool constructed according tothe invention which can be gathered from the preceding description, canbe mentioned the fact that the frame member I8 is detachable by removinga single fixing means, that is the union nut l I.

In some cases a collector may be provided for the punchings, such forexample as indicated in dotted lines at the lower part of Fig. 2, whereis a hollow cylindrical container of desired length, 50 which can beattached to the exterior of the cap 4| by a screwed bayonetor otherJoint into which the punchings can fall through the slot 42.

Although the section of the punch shown in the drawings is one which inpractice has given good results, it is to be understood that there-entrant portion can be other than a bend or curve. For example, itmay be of angle, channel or other form, or any desired combinationthereof. Similarly, the front and lateral portions of such section maybe varied, but preferably the lateral portions are convergent.

In the form shown in Fig. 13, the punch has a somewhat hexagonal sectionthe re-entrant portion being a channel with diverging walls 56 whilst 85the exterior has the ends 51 of the lateral portions flat andconvergent.

Again, variations may take place in the construction of the die. Forexample, only substantially the front half in the particularconstruction described need be used and the slot Ill replaced by aspace. Further, in place of screws such as 44, other means can beutilised to keep a die having only an active front part and adiscontinuous or open rear part, or even without such rear part, in

position.

' of the tool.

Further, instead of being located bya cap other means may be employedand the front shape may also be varied.

Although for most purposes it is preferred that the tool having there-entrant portion by its rear 5 surface should ride in contact with theportion of the frame member with which it co-acts, yet such actualcontact may not be necessary. For example. in some cases, the framemember although projecting into the re-entrant portion,'may not 10actually contact therewith. Such an example is shown in Fig. 12, fromwhich it will be seen that although the actual construction is somewhatsimilar to that shown in Fig. 8, yet the projecting part of the framemember 36 does not form a 15 bearing surface for the re-entrant curvedsurface However, it is preferred that the rearmost edges of the saidtool should have a guide, for example by the stepped formation 54.

The invention is not limited to the pecise forms 20 or details ofconstruction described, as these may be varied to suit particular cases.

What I claim and desire to secure by Letters Patent of the United Statesof America is:

1. A nibbling machine combining a relatively 25 fixed frame member, areciprocating punch carried thereby and a cooperating die, the saidframe member extending to one side of but adjacent the reciprocatingpunch, said punch having an operative punching section including are-entrant portion towards the extending frame member into whichre-entrant portion a part of the frame member projects for the purposeset forth.

2. A nibbling machine as claimed in claim 1, in which the die has onlyactive front and lateral 35 portions, the other portion being free ofthe frame member.

3. A nibbling machine as claimed in claim 1 in which the punch has anoperative section of substantial crescent shape. 40

4. A nibbling machine as claimed in claim 1, in which the re-entrantportion of the punch consists of a circumferential arc of somewhat lessthan terminating in slightly diverging tangents, and in which the frontand lateral portions 45 of the said section are formed by the arc of a,circle of somewhat larger diameter and slightly more than a semicirclein extent.

5. A nibbling machine as claimed in claim 1, in which the frame memberhas a substantially 5o semi-cylindrical front portion to be receivedinto the re-entrant portion of the punch.

6. A nibbling machine as claimed in claim 1, in which said frame memberextends rearwardly from the portion engaging in the re-entrant part 55of the punch, said rearwardly extending portion being converging incross section.

7. A nibbling machine combining a relatively fixed frame member, areciprocating punch carried thereby and a cooperating die, said punch sohaving a re-entrant portion, said frame member having spaced-apart upperand lower portions substantially axially arranged with respect to thepunch, and an integral connecting portion having a part shaped to coactwith the re-entrant no portion of the punch, the upper portion of theframe being detachably attached and the lower portion carrying the diethereby to leave a mouth above the die to be engaged with thework-piece.

8. A nibbling machine as claimed in claim 7, 70 in which the shaped partof the connecting frame portion which engages in the re-entrant part ofthe punch, extends into the upper and lower frame portions.

.9. A nibbling machine as claimed in claim 7, 75

in which the die-carrying frame member is connected by a nut member.

10. A nibbling machine as claimed in claim 7,'

in which spring means are associated with the reciprocating punch forassuring the disengagement of the punch from the die.

11. A nibbling machine as claimed in claim 1,

' in which the die is carried by acircular plate-like part of the framemember, and a cap with attaching screws for said part.

12. A nibbling machine as claimed in claim 1, in which the machine isprovided with a manipulating handle and a driving motor operatively 14.A nibbling machine as claimed in claim 1, in which the punch includes are-entrant portion which consists of a front portion and another portionextending both laterally and rearwardiy from said front portion, the.re-entrant portion being directed towards the extending frame member andinto which re-entrant portion a part of the frame member projects forthe purposes set forth.

15. A nibbling machine as claimed in claim 1, in which the part of thedie which cooperates with the punch has a front portion and sideportions, which latter extend both laterally and rearwardly, the otherportion of the die being free of the frame member.

GEORGE HENRY WEBB.

